The present invention relates to the field of mining shovels. Specifically, the present invention relates to mechanisms for controlling the tilt angle of a dipper.
As shown in FIGS. 1 and 2, a conventional electric rope mining shovel includes a dipper 10 rigidly attached to a handle 14, and a pitch brace 18 provides a link between the handle 14 and the dipper 10. The dipper 10 is hoisted through a bank (not shown) by a cable or hoist rope 22 that is attached to a bail 24 and equalizer 26 and passes over a boom sheave 30. The bail 24 is coupled to the dipper 10, and the equalizer 26 is coupled to the bail 24. The dipper 10 includes a lip 34 for engaging the material in the bank. During the hoist phase, the dipper 10 is pulled upward through the bank by the hoist rope 22. The hoist rope 22 exerts a tension force on the dipper 10 through the bail 24 and equalizer 26, and the equalizer 26 maintains the tension force in an orientation that is tangent to the boom sheave 30.